Flare article

ABSTRACT

Disclosed is a novel pyrotechnic flare article. The flare comprises a cylindrical grain of a pyrotechnic flare composition containing a binder fuel, an oxidizer and a light emitter. The grain is encased in a tight fitting layer of a nonflammable plastic shrink film. The film forms at least two spaced apart flanges extending along the longitudinal axis of the cylindrical grain to prevent the flare from rolling when placed on its side.

Unite tates atet Alexander 1 Aug. 26, 1975 [5 1 FLARE ARTICLE 2,848,946 8/1958 Goebig 102/3711 2,980,245 4/1961 Stoker..... 53/30 S [75] Inventor: Claude P. Alexander, Ann Arbor, 3,037,620 5/1962 Douty I 206/65 Mlch- 3,050,429 8/1962 Baxby 156/86 3,168,090 2/1965 Bellhardt. 102/37.8 [73] Asslgnee' 323 2:: ggz Company 3,236,492 2/1966 Wetzig 102 371; 3,524,409 8/1970 Grifiithm. 102/374 22 Filed; 1973 3,528,370 9/1970 Gaither 102/378 [2}] Appl 422379 Primary Examiner-Robert F. Stahl R l t d US, A li i D Assistant Examiner-Harold Tudor [63] Continuation-impart of Scr. No. 199,448, Nov. 17, Attorney Agent or Firm-G16? Korfhage; Bruce 1971 aband0ncd M. Kanuch; Lloyd S. Jowanovltz 52 vs. (:1. l02/37.8; 102/374; 149/2; 1 1 ABSTRACT 264/3 B Disclosed is a novel pyrotechnic flare article. The flare [51] Int. Cl. C06D 1/10 comprises a cylindrical grain of a pyrotechnic flare [58] Field of Search 156/84, 85, 86; 102/378, composition containing a binder fuel, an oxidizer and 102/374; 206/4533, 56 AB; 53/30; 264/3 R; a light emitter. The grain is encased in a tight fitting 149/2 layer of a nonflammable plastic shrink film. The film forms at least two spaced apart flanges extending [56] References Cited along the longitudinal axis of the cylindrical grain to UNITED STATES PATENTS prevent the flare from rolling when placed on its side.

2,358,713 9/1944 Hutt 102/3752 4 Claims, 2 Drawing Figures PATENTED mesms INVENTOR. C /0u0 e R fl/exana er H T TORNE Y FLARE ARTICLE REFERENCE TO RELATED APPLICATION This application is a continuation-in-part of application Ser. No. 199,448, filed Nov. 17, 1971, now abandoned.

BACKGROUND OF THE INVENTION Signaling flares, also known as colored fusees, are widely used in the transportation industry. They are used by railroads for both day and night signaling as well as by truckers during emergency stops. Private motorists also find them useful for signaling during such stops. Presently available fusees are prepared by press-formation whereby a fuel, oxidizer and color emitter are pressed into a cardboard tube. Pressing techniques may involve the use of solvent dispersed polymeric binders which require devolatilization after pressing or dry-pressing in the presence of pitch or tar for binding purposes. In either case, the cardboard tube is necessary to lend physical integrity to the system. Such a system has two basic disadvantages. First of all, breakage of the tube results in crumbling of the loosely bound particles and subsequent cleanup problems. More importantly, the light output of such a system is reduced by the so-called chimney effect. This effect results from the fusee composition burning down into the tube at a more rapid rate than the tube burns off. While the burning is taking place inside the tube, light output is diminished.

Researchers in the pyrotechnic area have proposed that signaling fusees be prepared by mixing an oxidizer, light emitter and a heat curable polymeric binder fuel to form a flowable composition. This composition is then either pour cast or extruded into the desired configuration and heat cured to form a coherent grain. This type of fusee requires some sort of nonflammable casing to prevent uneven burning after ignition. Preferably such a casing should be adequate to prevent the fusee from burning down the side of the grain and yet avoid the aforementioned chimney effect.

It is an object of the present invention to provide a novel signaling fusee article.

An additional object is to provide such an article which does not contain a cardboard tube or other covering which can cause a chimney effect during ignition.

A further object is to provide an article which will burn evenly upon ignition. 7

An additional object is to provide such an article which will not roll when placed upon its side.

SUMMARY OF THE INVENTION The present invention comprises a novel flare article which comprises a cylindrical flare grain of a composition containing a binder fuel, an oxidizer and a light emitter. The grain is encased in a tight fitting layer of a nonflammable plastic shrink film. At least two spaced apart flanges are also provided extending along the longitudinal axis of the cylinder to prevent the article from rolling when placed on its side.

DETAILED DESCRIPTION The flare article of the present invention is prepared by extruding a mobile, heat curable flare composition into the desired configuration and curing it to a coherent grain. Alternatively, a pour castable composition can be cast into a mold and the mold removed after curing. The grain is then encased in a sheet(s) of heat shrink film which is sealed along its edges by the application of suitable heat such as by crimping the edges between the two jaws of an impulse sealer until layers of film are securely sealed together. For example, a sheet of shrink film is applied to both the top and bottom of a horizontally positioned grain and the sheets fastened together around the perimeter of the grain to make a substantially air tight article. The film is then heated to a temperature sufficient to shrink it tightly around the grain to position it in heat induced intimate conformity about the grain. The film should fit tightly to the body of the grain. This tight fit can be induced by merely shrinking the film. Adhesives and interaction between the film and binder of the grain (e.g. between carboxylic groups of the film and epoxy groups of the binders) can also be used to assure a tight fit. Excess film is cut off so as to leave two longitudinal strips of film extending from the grain at angles to each other constituting flanges on the article. Conveniently, flare articles containing a series of flare grains attached to each other are prepared by applying shrink film to several flares in the manner described here and sealing the film between and around the independent grains. Perforations can be provided in the shrink film between individual flare grains to permit separation of individual encased grains from the series of grains.

DESCRIPTION OF FIGURES FIG. 1 illustrates a flare article.

FIG. 2 illustrates a suitable series packaging arrangement.

One embodiment of the flare article is illustrated by FIG. I. A cylindrical grain of an extruded flare composition, 11, is wrapped in a nonflammable shrink film, 12. The film, which is preferably colored red, has been heat shrunk tightly around the grain and forms two longitudinal strips of film extending from the grain at 180 angles to each other, constituting flanges, 17, on opposite sides of the flare article. As with conventional flares, an igniter composition, 13, may be inserted in one end of the grain. The igniter composition is covered with a concave tube, 14, having a striker composition, 15, at its closed end. Optionally, a spike, 16, is inserted in one end of the grain.

A suitable series packaging arrangement is illustrated by FIG. II. A series of flare grains are packaged in accordance with the invention with perforations, 19, between the individual grains. In operation a flare article is separated from the series by tearing along the perforated line providing a flare article having two longitudinal strips of shrink film extending from the grain at 180 angles to each other constituting flanges on the article.

The film is tightly shrunk around the grain to position it in heat induced intimate conformity about the grain so that upon ignition the flare grain is prevented from burning down the side. The selection of a nonflammable shrink film prevents the flare from burning down the side after ignition. As used herein, the term nonflammable is intended to refer to those films which burn at a slightly slower rate than the flare composition. Total inflammability is not necessary. The strips provide an additional advantage by preventing the grain from rolling should it fall over in the presence of a breeze.

The flare grain can be prepared from any extrudable composition comprising a binder fuel, light emitter and oxidizer. When a colored flare is desired, the composition disclosed in US. Pat. No. 3,508,518 is effective. The composition disclosed in US. Pat. No. 3,432,370 is especially effective when an illuminating flare is desired. Optionally, magnesium and Sr( NO can be combined as a light emitter to provide a colored flare having increased light intensity. The only critical property of the composition is that it be extrudable after mixing and, after extrusion, that it be curable to a coherent grain.

Among those nonflammable shrink films which may be used is Saran. A variety of other films may be employed. Also films which can be heat shrunk to fit tightly around the flare grain and are sufficiently inflammable so as to burn at a slower rate than the grain may be employed if they are sufficiently transparent to permit the light generated upon burning of the flare to be transmitted. It is, however, preferred that the film burn at, or slightly faster than, the burning rate of the grain. The relative rates can be controlled by the type of film employed, the thickness of the film, by controlling the rate of burn of the grain or by a combination of these and other factors. Various heat shrink films and their characteristics are discussed in Modern Packaging Encyclopedia, July 1971, Vol. 44, No. 7A, p. 188-192. Suitable equipment and processes are described in the same reference at pp. 438-446. Various films which can be employed include, for example, polyvinyl chloride, crosslinked polyethylene, polypropylene, polystyrene, polyesters and the like. The amount of shrinkage at various temperatures will vary in well known proportions, see for example the illustration found at page 189 of the above defined reference.

One type of sealing process which can be employed to prepare the articles of the present invention is described at page 438 of the above defined reference. In summary, the system is generally known as the L- sealer. The sealing bars are in the shape of a right angle. L-sealers operate with folded materials, although roll stock may be folded in-line on center folding equipment. Because the film is folded on one side, it is possible for the L-shaped sealing bar to produce fully sealed packages with each stroke of the head. In effect, the side seal of the next package is formed simultaneously with the preceding seal.

In operation, the product is inserted between two layers of folded film and moved to the sealing station. When the upper head of the machine is depressed, a fully encased package results. With hand-operated L- sealers, the package is then manually placed on the conveyor of the shrink tunnel.

EXAMPLE Two flare compositions were cast into cylindrical grains having a inch diameter and 10 inches long. One composition produced a red illumination and the other a green illumination when burned. The composition of the flares were as parts by weight: Red Flare parts of an epoxy-carboxy terminated polymeric binder; 46 parts strontium nitrate; 12 parts of strontium chloride (anhydrous); 18 parts of ammonium perchlorate and 4 parts of particulate magnesium. Green Flare 28.24 parts of an epoxy-carboxy terminated polymeric binder; 60.00 parts of barium chloride (hydrated) and 11.76 parts of barium carbonate. One of the red flare grains was wrapped with two layers of paper masking tape, each layer having a gauge of about 6 to 7 mils. A second red flare grain was encased in a single layer of 200 gauge Saran shrink film in the following manner. The grain was placed between two sheets of the film. The two sheets were then heat sealed around their entire perimeter with an impulse sealer having two heated jaws which crimped the sheets together While they were heated. The encased grain was then heated with hot air at a temperature of about to 200F until the film had shrunk tightly around the grain. A third red flare grain was encased in two layers of Saran film (one sheet of 100 gauge and one sheet of 200 gauge) in the same manner as the second grain was encased. Each flare was then ignited and the illuminating effect visually observed. Both of the Saran encased flares burned with a brilliant red color with no ascertainable chimney effect. The masking tape wrapped flare was less brilliant and a chimney effect was observed even though it was a much thinner coating than the Saran. The burning rates were determined as:

tape covered 0.012 in./sec.

two layers of Saran 0.016 in./sec.

one layer of Saran 0.187 in./sec.

One of the green flare grains was encased in two layers of Saran in the manner described above and one green flare grain was covered with two layers of the masking tape. The green flares when ignited were observed to have similar illuminating and chimney characteristics as the red flares encased in the same way. The burning rate of the masking tape covered flare was 0.017 in./sec. and the Saran encased 0.022 in./sec.

What is claimed is:

l. A pyrotechnic flare article which comprises in combination:

a. a generally cylindrical pyrotechnic flare grain containing a binder fuel, an oxidizer and a light emitter, forming the body of said flare,

b. a tight fitting outer layer of nonflammable plastic shrink film adhering to the surface of the grain to form the outermost portion of said flare and at least two spaced apart strips of said film extending from the article along the longitudinal axis of said cylindrical grain, said film and pyrotechnic composition having burning characteristics such that no burning down the sides of the grain and substantially no chimney effect occur upon burning of said flare grain.

2. The article of claim 1 wherein the shrink film is a copolymer of vinyl chloride and vinylidine chloride.

3. A fiare article which comprises in combination:

a. a generally cylindrical flare grain of a composition containing a binder fuel, an oxidizer and a light emitter, forming the body of said flare, and

b. a close fitting outer layer of a non-flammable plastic shrink film encasing the surface of the grain positioned in heat induced intimate conformity about the flare grain to form the outermost portion of said flare said layer also forming two longitudinal strips of film extending from the grain at 180 angles to each other constituting flanges on opposite sides of said flare article, the shrink film being chosen such that no burning down the sides of the grain and substantially no chimney effect occur upon use of said flare article.

4. The article of claim 3 wherein the shrink film is a copolymer of vinyl chloride and vinylidene chloride. 

1. A PYROTECHNIC FLARE ARTICLE WHICH COMPRISES IN COMBINATION: A. A GENERALLY CYLINDRICAL PYROTECHNIC FLARE GAIN CONTAINING A BINDER FUEL, AN OXIDIZER AND A LIGHT EMITTER, FORMING THE BODY OF SAID FLARE, B. A TIGHT FITTING OUTER LAYER OF NONFLAMMABLE PLASTIC SHRINK FILM ADHERING TO THE SURFACE OF THE GRAIN TO FORM THE OUTERMOST PORTION OF SAID FLARE AND C. AT LEAST TWO SPACED APART STRIPS OF SAID FILM EXTENDING FROM THE ARTICLE ALONG THE LONGITUDINAL AXIS OF SAID CYLINDRICAL GRAIN, SAID FILM AND PYROTECHNIC COMPOSITION HAVING BURNING CHARACTERISTICS SUCH THAT NO BURNING DOWN THE SIDES OF THE GRAIN AND SUBSTANTIALLY NO CHIMNEY EFFECT OCCUR UPON BURNING OF SAID FLARE GRAIN.
 2. The article of claim 1 wherein the shrink film is a copolymer of vinyl chloride and vinylidine chloride.
 3. A flare article which comprises in combination: a. a generally cylindrical flare grain of a composition containing a binder fuel, an oxidizer and a light emitter, forming the body of said flare, and b. a close fitting outer layer of a non-flammable plastic shrink film encasing the surface of the grain positioned in heat induced intimate conformity about the flare grain to form the outermost portion of said flare said layer also forming two longitudinal strips of film extending from the grain at 180* angles to each other constituting flanges on opposite sides of said flare article, the shrink film being chosen such that no burning down the sides of the grain and substantially no chimney effect occur upon use of said flare article.
 4. The article of claim 3 wherein the shrink film is a copolymer of vinyl chloride and vinylidene chloride. 